Brake and/or main control equipment for use in railway vehicles have been known in the prior art. See, for example, Japanese publication Jitsukaisho 57-58906 and jitsukaisho 61-54966. The control equipment taught in these publications is representative of the prior art control equipment and are illustrated in FIGS. 3 and 4 of this application.
As shown in FIG. 3, the prior art control device includes an upper cover designated 1a and a lower cover designated 1b. The upper cover 1a and lower cover 1b each constitute a portion of the main body of the prior art control device. Through bearings designated 2a, which are engageable with the upper cover 1a, and 2b, which are engageable with the lower cover 1b, a rotatable shaft 3 is positioned between such upper cover 1a and lower cover 1b for free rotation. A control wheel or handle which has not been illustrated in FIG. 3, is attached to the projecting end of such rotatable shaft 3.
Multiple numbers of boards 4 which are provided for detection are mounted at approximately a perpendicular orientation to the rotating shaft 3 (left-right direction in the figure). The rotating shaft 3 which is interlocked with the handling operation and the contactless switch 5 which detects the rotational position of each of those boards 4 for detection is mounted on the side wall (not shown) of the main body. When the board 4 for detection rotates following the operation of the handle, the contactless switch 5 detects the location and outputs an electrical signal which serves as either a deceleration or acceleration command.
In addition, the above-mentioned detection board 4 can be replaced by a light blocking board, and the contactless switch 5 by a transparent light switch, or the detection board 4 can also be replaced by a reflecting board and the contactless switches 5 by a reflective light switch. Furthermore, the board 4 for detection and the contactless switch 5 may consist of a proximity body and proximity switch respectively.
Even in a controller apparatus using the contactless method for position detection, as in the case of the contact-type controller apparatus using conventional cam and cam switch, a similar control resistance addition mechanism is used, as shown in FIGS. 3 and 4. The case of the brake controller is illustrated in FIG. 4.
On the periphery of the star wheel 6 fixed approximately perpendicular to the axial direction of the rotating shaft 3, there are grooves 6a in locations corresponding to each of the handling locations. The numbers 1-7 indicated on this star wheel 6 are the respective step positions of the conventional braking range of a railway vehicle. In this prior art controller apparatus, the roller 7 that makes contact with the outer periphery of the star wheel 6 is supported so that it can rotate freely by means of a pin 10, at the tip of a lever 9 which is axially supported by a pin 8 at the base on the main body side. In order to press this roller 7 against the outer periphery of star wheel 6, there is a spring 11 installed between the support body 12, attached to the main body and the above lever 9. Here, 12a is an adjusting screw and 12b is a spring receiver.
In this prior art mechanism for the addition of control resistance, the roller 7 is pressed into the groove 6a of the star wheel 6 by the force of spring 11, and when the roller 7 tries to slip out of groove 6a, the spring 11 is compressed, and the roller 7 tends to maintain its position in the groove 6a, and the reaction which takes place in the star wheel 6 at this point is the control resistance. Therefore, by rotating the rotating shaft 3 to the position where the roller 7 fits in the groove 6a, by a control action, that position can be ascertained.
This prior art controller apparatus has certain problems in that, when this controller is the brake controller, there are grooves 6a on the outer periphery of the star wheel 6, corresponding to the respective positions of steps 1-7 of the standard operation of the railway vehicle braking range. When the control handle is set to steps 1-7 of the normal braking range of the railway vehicle, the roller 7 engages and disengages from the groove 6a to produce digital handling resistance of the ON-OFF mode and the control resistance of this digital type response gives an unfamiliar feeling to operators who are more accustomed to the pneumatically-controlled brake valve which is different from the controller apparatus in question. Also, when this controller apparatus is the main controller, the power control range is divided into 1-4 steps or 1-7 steps and there are numerous grooves 6a on the outer periphery of the star wheel 6, which again gives an unfamiliar feeling to operators, like the case described above.
In order to eliminate this unfamiliar feeling, grooves 6a corresponding to each step of the standard braking range on the power control range may be eliminated, and the surface of the outer periphery which corresponds to the star wheel may be made smooth, without projections and recesses.
However, if the face is uniform, the roller 7 in contact with this face rotates freely. Its rolling resistance is very low, and since the control position detection mechanism is of the contactless type, and has no switching resistance like the conventional contact type, and furthermore, since the rotating shaft 3 is supported only by bearings 2a and 2b, the control resistance becomes extremely low, and it becomes difficult to maintain the control handle at a desired step position of the standard braking band or power band.
One approach may be to make the roller 7 be of the fixed type and also to make the force of the spring 11 stronger, but then, since the contact area of the outer periphery of the star wheel 6 and the roller 7 is small and the surface pressure per unit area becomes very high, there will be a problem of excessive wear on these parts in contact.